News from the Society for Astronomical Sciences

Transcription

1 News from the Society for Astronomical Sciences Vol. 16 No.3 (July, 2018) Recap of the SAS-2018 Symposium Roughly 120 people attended the SAS-2018 Symposium, to hear technical presentations of smalltelescope science projects and results, learn new ideas during the Workshops, and to gain insights from the professional astronomers whose research intersects with the interests and capabilities of smalltelescope scientists. Dr. Lance Benner entertained and educated us on the recent radar observations of asteroids, and suggested that we pay continued attention to 3200 Phaethon, since it is likely to be the target of a future Japanese space mission. Dr. Jennie Christiansen brought us up-to-date on the status of TESS, and the ongoing plans for pro-am collaboration on that mission. Her talk was also a good match to Dennis Conti s discussion of false positive exoplanet transits (and how to distinguish them), which will be an important task for smalltelescope photometry throughout the TESS mission. Since this was a joint meeting with the Association of Lunar and Planetary Observers, there was plenty of discussion of solar system objects and projects. For example Richard Schmude s talk about Mars polar cap prompted suggestions to monitor (a) the albedo of the North Polar Cap, using resolved photometry; (b) polarization of Martian features; and (c) cloud Attendees at the 2018 SAS Symposium opacity. During the spectroscopy lunch discussion, someone pointed out that there would be value in a project for long-term monitoring of Uranus methane bands, and their changes over time (low resolution will be sufficient, Δλ 5-10 nm). Another idea that bubbled up was to try drift-scanning of a slitspectroscope across Jupiter (sort of like a spectroheliograph), to create separate images in Hα, methane, etc.) Quite a few photometry results were on display, including eclipsing binary and pulsating stars; and the challenge of understanding and improving the accuracy and precision of stellar photometry. Add in double-star astrometry, solar flares and variable stars in other galaxies, and this year s Symposium pretty well spanned the universe, and illustrated the breadth and depth of smalltelescope research activities. The Proceedings of SAS-2018 are now available on the SAS website (go to the Publications tab). Videos of many presentations will be uploaded within the next few weeks. SAS Election Results SAS is a non-profit public benefit corporation incorporated in California, which is managed by a Board of Directors. The following Directors were elected to three-year terms: Robert Buchheim (President) Robert Stephens (Treasurer) Robert Gill (Secretary) Jerry Foote John Menke Wayne Green Dr. John C. Martin 1

2 Their term of office is through June, We congratulate these members on their election, and thank them for volunteering their time to the SAS. Planning for SAS-2019 The SAS Committee is already thinking about next year s Symposium. We have tentatively selected May June1 for the Symposium, which will be held in Ontario, California. If you have ideas about how to make the Symposium more useful to the small-telescope research community, specific topics that you would like see on the agenda, or other thoughts, please share them with the Program Committee, at: Program@SocAstroSci.org. We look forward to hearing your input and advice! Reminders for SAS Members... Membership Renewal: Even if you can t attend the annual Symposium, we value your support of the Society for Astronomical Sciences, and your interest in small-telescope science. As an SAS member, you will receive a bound copy of the Proceedings on request, even if you cannot come to the Symposium. Symposium Proceedings: Published proceedings from all recent Symposia are freely available in PDF format at the PUBLICATIONS tab of the SAS website ( Symposium Videos: If you missed a recent Symposium, you can watch many of the presentation videos on the SAS website at the PUBLICATIONS tab. Workshop Videos: Video recordings of most of the Workshops from recent years are available from SAS. If you were registered for the Workshop, then the recording is free. If you were not a registered attendee, then the price is $25 per workshop. Contact Bob Buchheim (Bob@RKBuchheim.org) for the details. Keeping in Touch: The SAS Yahoo group ( SocAstroSci ) is a good way to keep in touch with the members and participants. Kudos, Criticisms, or fresh Ideas? If you have any questions or ideas for the Symposium, ideas for Workshops or Technical topics that you would like to see, or comments on any other subjects related to the Symposium, please share them with the Program Committee at program@socastrosci.org. The EU General Data Protection Regulation The EU GDPR came into force a few months ago. It requires that organizations like ours protect the personal data (names, addresses, etc.) of EU residents that are in our database; and to give them the opportunity to change or delete such data. There are only a few EU residents in our database. If you are one of them, you will soon receive an describing the data that we have, and asking for your consent to continue to use your information in our database for SAS purposes, such as processing financial transactions (e.g. Membership dues and Symposium registration) and communication of SAS news. Beyond this unique legal requirement, all SAS members can read our Privacy Policy on the SAS website ( SAS_Refund_and_Privacy_Policy.pdf) SAS never gives or sells your information to any other organization without your express permission. If you have any questions about this subject, feel free to contact us. Unsolicited Publishing Request Some of you may have received an e- mail publishing request from Lambert Academic Publishing, soliciting submissions of papers to one of their journals. (Your editor received such an e- mail, shortly after the SAS-2018 Symposium). SAS has no relationship with Lambert Academic Publishing. We did not provide them with a list of papers or presenters or any other information; nor do we have any plans to form such a relationship with Lambert. The SAS Proceedings are freely available on our website, so it is plausible that Lambert may have fished author contact information from that source. We recommend that you investigate the sender before responding (just as you would with any other unsolicited offer). Discussion group on Small Space Telescope 2

3 Views from the 2018 SAS Symposium & joint meeting with ALPO (photos by Bob Stephens & Bob Buchheim): Learning about new products Registration Dr. Bob Nelson (out-of-eclipse) This is what happens when you ask a seemingly-simple question... Chris Butler (banquet speaker) Raffle Winners & Donors 3

4 Symposium Sponsors The Society for Astronomical Sciences thanks our Sponsors for their participation and financial support. Without them, our Symposium would not be possible. We encourage you to consider their fine products for your astronomical needs. Sky & Telescope Magazine The Essential Magazine of Astronomy DC3 Dreams Software Developers of ACP Observatory Control Software PlaneWave Instruments Makers of the CDK line of telescopes Woodland Hills Camera & Telescopes Providing the best prices in astronomical products for more than 50 years Sierra Remote Observatories Hosting telescopes for remote imaging and data acquisition QHYCCD Innovative imaging and observatory products SBIG Imaging Systems Award winning imaging systems for astronomical and laboratory use. Software Bisque Enriching your astronomy experience since

5 Book Review: Successfully Starting in Astronomical Spectroscopy a Practical Guide by Francois Cochard (EDP Sciences, 2018) This wonderful book is exactly what it claims to be: A practical guide that takes you from a standing start to making high-quality, accurate stellar spectra that can be used for education or research. The author is President of Shelyak Instruments, the dominant provider of commercial spectroscopes for the amateur market, so he knows what he s talking about. There are quite a few excellent books about astronomical spectroscopy available today. They explain the physics behind the generation of spectra and discuss the interpretation of stellar spectra, and aim at readers of different scientific and mathematical sophistication. This book has a very different goal: it may be the only one on the market today that is dedicated to teaching you how to actually use your telescope, slit-spectrograph, and CCD camera to take a spectrum image, and then translate that image into a spectrum profile that is wavelength-calibrated and corrected for instrumental response. (He specifically avoids the slitless spectrograph, since it is quite a different beast and quite a bit easier for the beginner to understand and use). Not surprisingly, the examples and illustrations are all from Shelyak spectrographs (mostly the ALPY-600), but the author s advice applies to any instrument that the beginner might use. And it is sage advice: The telescope and mount, the spectrograph, and the CCD camera are each fairly complicated systems. Learn to understand and use each one, on its own, before you start putting them together. Gain experience with each system in the daytime, before moving to night-time experiments. To this end, he gives detailed explanation of the requirements and experience the user should gain with her telescope/mount, then (separately) with the spectrograph on a bench, then with the CCD on the bench and telescope, and finally putting it all together. For the first night-time activities, select a few bright stars and fully understand how to focus your telescope, confirm its pointing and tracking capability, then understand and characterize your science camera and guiding camera, and finally take a few bright-star spectra. During your first night-time spectroscopic experiences, use manual guiding rather than autoguiding. It will teach you quite a bit about the unique characteristics (and problems) of your setup. A spectroscopic observation consists of several types of images: the target star, a reference star, a calibration lamp, a flat lamp, bias and dark frames. Plan and schedule all of these in order to be able to create a scientific-quality spectrum. Work through the image-processing and spectrumprocessing steps so that you understand the procedure; and then standardize the procedure you will use. Practice continuous improvement : compare your results to stellar spectral libraries, to other people s results, and discuss your observations and challenges with knowledgeable friends. By working together and sharing information, we can all improve the quality of our results. He also does a fine job of discussing parameters for matching the telescope, spectrograph, and cameras. He covers focal length and F/#, atmospheric seeing, slit size, dispersion and spectral range, and sampling in the CCD array, with the equations and logic that enable you to understand how well your components are likely to work together. If you are new to small-telescope spectroscopy, this book is a worthwhile (maybe essential) investment. Even if you have some experience, it is likely to offer useful insights into both the mechanics of making spectrum-images, and the process of turning them into spectrum profiles. This isn t a user-manual for the software ISIS, but most of the processing steps are explained with reference to ISIS. Hence, you ll get a good overview of how that fine software package works. Because the book is aimed at the beginner, it focuses primarily on low-resolution spectroscopes, the ALPY-600 in particular. This makes sense, because all of the principles are more easily understood when you re looking at low-res spectra, and a low-res instrument is easier to use and more forgiving than a high-resolution instrument. He offers some valuable advice for users of higher-resolution instruments 5

6 e.g. Shelyak s LHires unit), but it tend to be in the nature of oh, by the way... as part of the low-res discussion. That is my one quibble about the book: I would have appreciated an additional chapter that discussed the special peculiarities of higher-resolution instruments using the LHires-III as the example (e.g. increased sensitivity to mechanical and thermal distortion, adjusting the grating tilt to select the spectral range, calibration methods, issues with ever-longer exposure sequences...). Nevertheless, people whose first spectrograph is a high-resolution unit are likely to benefit from all of the advice in this book. In particular, his overriding emphasis on learning (and adjusting) your equipment in a logical, step-by-step sequence, taking one system at a time (e.g. the telescope and mount alone, the spectrograph alone on a bench in the daytime, etc.) will be valuable, and is likely to help those users who are struggling to use their LHires units effectively. The difference between low- and high-resolution in this regard is that each individual step is more important and each adjustment is more sensitive with the higher-resolution system, so that the step-by-step approach is even more essential. The book was originally written in French, and then translated into English. The translation is excellent, the writing is smooth and the entire discussion is presented in a straightforward and readily-understandable way. The list price seems to be about $100, but I got my copy from Amazon for about $60. It s well worth it! Bob Buchheim Looking for Motivation in Small-Telescope Spectroscopy? At the recent OHP Spectroscopy camp, Dr. Steve Shore gave a brief wrap-up, that you can watch here: He noted the evolution of detectors and spectrographs over the last 100 years, and the wonderful current state of the art of spectroscopy for small telescopes: This is a new world. Open up what you re looking at. Objects that have not been looked at for 50 years, should be looked at again. Those that couldn t have been looked at that people just speculated about go back and start on those. You re not going to be competing with anybody; you re going to be adding. Anything you do, adds, as long as it s reliable. Spectroscopy Targets of Interest: Chemically-Peculiar stars Making an Observing List From a Paper's Data by Wayne Green Over coffee one morning I encountered a report of a database of approximately 400 peculiar metallicity stars. I noticed the abstract showed the general spectral type was ApBp. The paper is: New catalogue of Chemically Peculiar stars, and Statistical Analysis by S. Ghazaryan, G. Alecian and A. A. Hakobyan. The pre-print is available at Footnote 1, on page 2 has an incorrect address for the catalog. The correct address is: The The abundances database link of this page has information about the star's metallicity, but no ra/dec information. In order to make an observing list, the coordinates are needed, of course. The goal of the exercise is to tie coordinates to the list of stars. SIMBADs Script submission' query mode will come to the rescue. Off to SIMBAD. I used my text editor to prepare a file that I could upload. The file is in essentially two parts: 1) the format statement asking for data in the order and format that I want it returned and 2) the list of stars. Note: In the code listings below, I have broken very long lines with three-dots (ellipsis...) for easier viewing. Here is the format statement (part1) format object f1 " %IDLIST(A;WDS,HIP,HD)[%*( S )]... %COO(2d;A D) %RV(rv=V) %PM (A D P Q) %PLX(V E)... spectype %SP(s) fluxes %FLUXLIST(;N=F,) %OTYPELIST(S)" and the first of 430 lines with the list of stars to find: 6

7 query id wildcard HD358 query id wildcard HD query id wildcard HD query id wildcard HD35497 query id wildcard HD53244 query id wildcard HD The Help page for this process is complicated and a bit obtuse. I've been staring at this page for years and have gotten somewhat used to what I can do. I have the template that I like to use saved as a file. I usually start with a small example, and fiddle with the format statement until what I asked for appears. Explanation of the format statement The system returns a lot of lines, one line per star. The trick is to split that returned file into the right parts and then make a clean list. I use python usually hacking something together to write a csv file. All the delimiters need to be removed. Note: I add the vertical bar character (' ') to separate the fields, and most sub-queries on each line. This character almost never used and is pretty safe to include as a separator. SIMBAD forces you to use different separators sometimes, for example the semicolon in the IDLIST phrase. So let s look at each sub-query one at time. Here are the phrases broken out onto a separate line for each. %IDLIST(A(,);WDS,HIP,HD)[%*( S );]... %COO(2d;A D)... %RV(rv=V)... %PM (A D P Q)... %PLX(V E)... spectype %SP(s)... fluxes %FLUXLIST(;N=F,)... %OTYPELIST(S) The %IDLIST is a complicated one. The command phrase starts with %IDLIST and is followed by a modifier sub-command in parenthesis that holds a list-of-acronyms (catalog designators). I used catalog designators for WDS, HIP and HD catalogs. The A(,); tells the sub-query there is a list coming with my catalog designators separated by a comma. Whitespace is significant, so I am supposed to splice the prefixes together only with the comma character. The part in square brackets [] holds a percent sign (%*( S );)' string that will use a semicolon as the separator between catalog designations for the star. When I split this out I take the larger string and sub-split on the semicolon. That sub-field comes back as: WDS J Aa,Ab;WDS J A;HIP 677;HD 358; The %COO command phrase tells SIMBAD how to return my coordinates. %COO is the command and (2d;A D) is the command modifier. SIMBAD thinks it's cute to put the coordinates out as space-separated parts all in one lump. I have found it much easier to use decimal degree coordinates for everything separated into distinct fields. To separate these fields the modifier must be a vertical bar for the RA and DEC separator. This means I get two vertical-bar separated parts, one each, for RA and DEC. That sub-field comes back as: The rest of my request returns details of interest: %RV(rv=V) returns rv= %PM(A D P Q) returns A %PLX(V E) returns %SP(s) returns B8IV-VHgMn %OTYPELIST(S) returns **,SB*,SB*,Star,PM*,V*,RotV*alf2CVn,IR,UV

8 Next the fluxes %FLUXLIST(;N=F,) command has my text fluxes followed by the command. In the options, the semicolon tells the command there are no real options, and the N=F, tells SIMBAD to return a list of (filter) NAME=FLUX values. I am interested in the general basic magnitude and not necessarily the error bars for the values. (yes I get a trailing comma, but it s SIMBAD). fluxes U=1.48,B=1.95,V=2.06,R=2.09,I=2.19,J=2.30,H=2.33,K=2.37, The final phrase OTYPELIST(S) gives me a list of the types of stars. (The type EM* is an emission star). The types returned are: **,SB*,SB*,Star,PM*,V*,RotV*alf2CVn,IR,UV (Note: RotV*alf2CVn is a Variable Star of alpha2 CVn type. Sometimes SIMBAD can be quite specific!) Here's the line returned for the first star: (Again the... is where I break the line into a printable form): WDS J Aa,Ab;WDS J A;HIP 677;HD 358; rv= A spectype B8IV-VHgMn... fluxes U=1.48,B=1.95,V=2.06,R=2.09,I=2.19,J=2.30,H=2.33,K=2.37,... **,SB*,SB*,Star,PM*,V*,RotV*alf2CVn,IR,UV The type values, where known, are reported for most of the stars. It is often the case with various authors, that they use an older catalog or typeset the fields for certain catalogs (like 2MASS) with a slightly different notation from the form stored in the SIMBAD database. This requires a bit of teasing the list to get a good result. This paper used the older UCAC3 catalog. Missing Stars What about the stars that were not found? [80] 'USNOA ': No known catalog could be found [81] 'USNOA ': No known catalog could be found [82] 'USNOA ': No known catalog could be found [325] 'CD ': this identifier has an incorrect format for catalog: CD : catalogue CD I pop over to SIMBADs by name form and explore the catalog designators. The USNO catalog designators are usually part of the long list for a HIP/HD star. So I take a known star and start the investigation. HIP 677 = USNO-B where the USNO is shown as a hyperlink. It tells me that SIMBAD is using a later catalog name, with the hyphen character being significant. So off to VizieR. In the USNO-A2.0 catalog the star designator is a 4 digit zone, a dash, and a 8 digit ID for the star in that zone (no coordinate info here). I use correctly adding the dash. Sure enough VizieR finds that star at coordinates of Back to SIMBAD for a small cone search using the by coordinates page. Using coordinates with the format d (all run together) for the VizierR query returns: 8

9 identifier typ coord1 (ICRS,J2000/2000) UCAC * MASS J RG* UCAC * The winner is UCAC which is using a completely different catalog format from the UCAC3 catalog. Summary For a large study or for lots of targets it is critical to report the right ascension and declination of each observation's target(s) to facilitate others finding, observing or studying your targets. It is helpful to have good research and software/query skills to drill down into other people s nomenclature where you want make your own observations. The emerging standard is SIMBAD and VizieR -- but some groups prefer to maintain their own databases. The GAIA DR1 data is now reported in SIMBAD (remember bright stars are not included in the GAIA survey). The field of astro-informatics is in the early stage. Currently there is a movement to scrape information from papers to make databases more robust. This leads to errors. Ideally, each object would have a very unique identifier that is independent of its position or any other quality. That identifier can then be tied to a master set of information elements for that object. This is a complex problem when you might consider one older star turns out to be a multiple star system. In all cases, we have to take these databases as we find them, take the subset of information, and improve precision to meet our needs. Conclusion The paper that started this little expedition contains a number of very bright stars, worthy of study with a small spectrograph. I am unaware of any long term survey of peculiar stars. BeSS is providing a goodstudy of B[e] and related early emission stars. My next steps are to transform the Simbad data into a database table and cross-correlate with the author s data. I can then produce my observing list. The Script Execution feature is very useful, and a bit easier to approach that using a direct SQL database language query. In reality, the ADQL TAP database query can be used to shorten the list to only peculiar metallicity stars that are emission stars.

10 SAS Leadership Corporate Officers: Bob Buchheim President Robert Stephens Treasurer Robert Gill Secretary Newsletter Editor: Robert Buchheim Sponsor & Vendor contact: Jerry Foote Cindy Foote Registration: Lorraine Moon Eileen Buchheim Allyson Hearst All SAS Leaders are volunteers, serving without compensation. Advisors: Dr. Arne Henden Dr. Alan W. Harris Dr. Dirk Terrell Membership Information The Society for Astronomical Sciences welcomes everyone interested in small telescope astronomical research. Our mission is to provide education, foster amateurs participation in research projects as an aspect of their astronomical hobby, facilitate professionalamateur collaborations, and disseminate new results and methods. The Membership fee is $25.00 per year. As a member, you receive: Discounted registration fee for the annual Symposium. A copy of the published proceedings on request each year, even if you do not attend the Symposium. Membership application is available at the REGISTRATION page of the SAS web site: The SAS is a 501(c)(3) non-profit educational organization. SAS Contact Information 9302 Pittsburgh Avenue, Suite 200, Rancho Cucamonga, CA On the web: Program Committee: program@socastrosci.org Membership: Robert Stephens: rstephens@socastrosci.com Newsletter Submissions: Bob@RKBuchheim.org 10